Just a little bit of info to help you all keep track of who is who. Not a lot of info though, because we're only 3 chapters in and I don't want to give spoilers. Hopefully I'll remember to update this as we go on. Someone commented on OOTD asking for pictures since they weren't familiar with all the girls, so I included those. I tried not to make them too big and honestly once you start looking small, there's not a lot of variety but pretty much this is what they look like at maturity in my head, if you have an era that you love and that's how you picture them then of course imagine them however you want to! (IMAGES FROM GOOGLE. NOT MINE)

In order of when they are introduced in the story.

Amber— Telekinesis/Empathy (Lu Han)—the first Guardian to be discovered. She was realized as a Guardian at age 5, reached maturity at age 20. Her “sister” is Yoona (mentored by Sehun).

Victoria (Birth name Qian)—Healing (Yixing). She was realized as a Guardian at age 5, reached maturity at age 23. She has potential to be a leader, due to her motherly personality.

Luna (Birth name Sunyoung)—Light (Baekhyun) She was realized as a Guardian at age 3, reached maturity at age 18. Her “sister” is Hyoyeon (mentored by Chanyeol). She got her nickname because she makes lights that look like the moon.

Sooyoung—Water (Suho) She was realized as a Guardian at age 7, reached maturity at age 20. Her “sisters” are Krystal (mentored by Kris) and Jinri (mentored by Tao).

Jinri (Real-life stage name: Sulli)—Time control (Tao). She was realized as a Guardian at age 3, reached maturity at age 16. Her “sisters” are Sooyoung (mentored by Suho) and Krystal (mentored by Kris).

Nana (Im Jinah)—Speed (Kai/Jongin). She was realized as a Guardian at age 8, reached maturity at age 20. She may not be able to teleport, but she can break the sound barrier. Her power is most similar to Jongin’s, which is why he was chosen as her mentor. Her “sister” is Sunny (mentored by Jongdae).

Sunny—Lightning (Chen/Jongdae). She was realized as a Guardian at age 7, reached maturity at age 20. Her “sister” is Nana.

Tiffany—Strength (Kyungsoo). She was realized as a Guardian at age 6, reached maturity at age 20.

Hyoyeon —Fire (Chanyeol). She was realized as a Guardian at age 6, reached maturity at age 20. Her “sister” is Luna.

Jessica—Frost (Xiumin/Minseok). She was realized as a Guardian at age 7, reached maturity at age 20. Her biological sister is Krystal.

Yoona—Air (Sehun). She was realized as a Guardian at age 5, reached maturity at age 19. Her “sister” is Amber (mentored by Lu Han).

Krystal —Flight (Kris). She was realized as a Guardian at age 5, reached maturity at age 16. Her biological sister is Jessica, and her sisters by mentor-relationship are Jinri and Sooyoung. She has potential to be a leader, due to her intelligence and deep spirituality.